The invention relates to fire extinguishers using an explosive charge to disperse a fire quenching solution. The prior art discloses a number of devices in which an explosive cartridge or the like is placed within an extinguishing medium.
Pierce U.S. Pat. No. 764,763 illustrates an early approach towards such a device where a waterproof cartridge shield intrudes into a holder containing an extinguishing agent. Owing to the construction of the Pierce device, the cartridge shield consumes a considerable portion of the holder's volumetric capacity, reducing its fire quenching ability. Furthermore, the shape and placement of the cartridge shield permit the brunt of the explosive thrust to take the path of least resistance and expel through the fuse inlet aperture. Thus, the substantially non-compressible aqueous solution around the shield will not be dispersed either as widely or in such a uniform pattern as may be desired to achieve optimum results.
The patent to J. H. Walrath, U.S. Pat. No. 750,416, displays the same disadvantages pointed out in the Pierce design, but uses a dry extinguishing powder rather than the aqueous extinguishing solution used in the present invention.
There is, in other words, considerable room for improvement.